The present invention relates generally to solid rocket boosters. More particularly, this invention pertains to a case-burning solid rocket booster.
Core-burning solid rocket boosters are known in the art and are typically fast burning systems that produce large amounts of thrust. These systems burn solid rocket fuel from the inside of the solid rocket fuel core outward to the pressure containing case enclosing the core. This type of burn pattern is designed to minimize exposure of the case to the intense heat of combustion.
While this type of burn pattern produces high thrust, it also produces short burn times and, as a result, core-burning solid rocket boosters require multiple stages to reach orbit or to propel long-range missile systems. Examples of typical multiple-stage solid rocket boosters are described in U.S. Pat. No. 5,070,691, issued to Smith et al. on Dec. 10, 1991 and entitled xe2x80x9cSolid Propellant Canister Loaded Multiple Pulsed or Staged Rocket,xe2x80x9d and U.S. Pat. No. 4,956,971, issued to Smith on Sep. 18, 1990 and entitled xe2x80x9cSolid Propellant Canister Loaded Multiple Pulsed Or Staged Rocket Motor.xe2x80x9d Multiple-stage solid rocket boosters, however, are more complex than single-stage solid rocket boosters and are undesirable in some applications for this reason.
Core-burning solid rocket boosters also usually include a layer of insulation on the interior of the case in order to further protect the case from the heat of combustion. In some applications, however, this layer of insulation is undesirable because it adds weight and decreases overall rocket performance.
What is needed, then, is a solid rocket booster system that reduces to one stage or minimizes the number of stages required to reach orbit or to propel a long-range missile system and that does not require a layer of insulation to protect the case containing the solid rocket fuel from the heat of combustion.
Accordingly, one object of the present invention is to provide a solid rocket booster that requires fewer stages to reach orbit or to propel a long-range missile system.
Another object of the present invention is to provide a solid rocket booster that does not require a layer of insulation to protect the case containing the solid rocket fuel.
These objects, and other objects that will become apparent to someone practicing the present invention, are satisfied by a case-burning solid rocket booster that includes a case containing a solid rocket fuel, a combustion chamber connected to the case for burning the case and the solid rocket fuel, a nozzle connected to the combustion chamber for expelling the burned case and fuel to generate thrust, and a drive system for pulling the combustion chamber and nozzle up the case as the case and fuel burn. In an alternative embodiment, a hybrid version of the case-burning rocket includes an oxygen supply system for supplying varying amounts of oxygen to the combustion chamber to vary the thrust generated by burning the case and the fuel. In either embodiment, the booster of the present invention burns the case as well as the solid rocket fuel and thereby increases the amount of thrust produced by the booster. As a result, fewer stages are required to reach orbit or to propel a long-range missile system. In addition, no layer of insulation is required to protect the case containing the solid rocket fuel for the booster of the present invention because the case is actually consumed during the combustion process thereby increasing overall rocket performance.